caging – noun

A method for preserving the validity of an election by restricting the voting rights of minorities who don't receive registered mail.

COMMENT: Those minorities who have their voting rights restricted aren't literally caged. That practice was formally banned after the Civil War, and legally banned after passage of the 1965 Voting Rights Act. Instead, they are simply prevented from voting.

And why should minorities who don't receive mail vote? How can they be informed voters if they refuse campaign literature?